甘草次酸对血管平滑肌细胞c-fos mRNA表达及细胞增殖的影响

Effects of glycyrrhetic acid on the expression of c-fos mRNA and cell proliferation in rat vascular smooth muscle cells

目的 研究甘草次酸 (GA)对大鼠血管平滑肌细胞(VSMC)原癌基因c fosmRNA表达及细胞增殖的影响 ,探讨GA与血管紧张素Ⅱ (AⅡ )受体结合的可能机制。方法 原代培养大鼠血管平滑肌细胞 ,[3H]TdR参入DNA、MTT分析法、Northernblot。结果 ①低浓度GA( 1× 10 -9mol·L-1)及高浓度GA( 1× 10 -5mol·L-1)均能导致c fosmRNA迅速表达 ;1× 10 -5mol·L-1Sar AⅡ能够阻断AⅡ、GA诱导的VSMCc fos表达 ;低浓度和高浓度GA都能促进AⅡ ( 1× 10 -5mol·L-1)诱导的VSMCc fos表达 ;②低浓度GA对细胞的增殖有促进作用 ;随着浓度的升高 ,促增殖作用减弱 ;高浓度GA抑制细胞的增殖。Sar AⅡ单独作用于VSMC ,不影响细胞增殖 ;Sar AⅡ能够阻断AⅡ对细胞增殖的促进作用 ;Sar AⅡ既抑制低浓度GA促细胞增殖作用 ,也消除高浓度GA抑制细胞增殖作用 ;低浓度GA与AⅡ联合作用 ,对细胞增殖的促进作用更加显著 ;高浓度GA与AⅡ联合作用于VSMC ,则可减轻高浓度GA对细胞增殖的抑制作用。结论 GA能激活c fos转录因子 ,从而产生对VSMC的增殖作用 ,因此 ,GA具有AT1受体的激动剂2 0 0 2 0 4 0 3收稿 ,2 0 0 2 0 7 2 3修回作者简介 :张凤云 ,女 ,33岁 ,硕士 ;贺师鹏 ,男 ,67岁 ,教授。研究方向

AIM To analyze the effects of glycyrrhetic acid (GA) on c-fos expression and cell proliferation in rat vascular smooth muscle cell (VSMC), and to figure out the mechanisms of binding GA to angiotensin Ⅱ(AⅡ) receptor. METHODS Primary cell culture of rat VSMC, Northern blot, TdR incorporation DNA assay and MTT assay were used in this study. RESULTS ① GA at both low (1×10 -9 mol·L -1) and high concentration (1×10 -5 mol·L -1) quickly induced c-fos expression in VSMC. Sar-AⅡ(1×10 -5 mol·L -1)inhibited both GA induced and AⅡ (1×10 -5 mol·L -1) induced c-fos expression. GA enhanced AⅡ induced c-fos expression at both low and high concentration in VSMC. ② Low level of GA stimulated the proliferation of VSMC. This stimulatory effect decreased with increasing GA concentration, and changed to be inhibitory at high concentration of GA. Not only did Sar-AⅡ eliminate the stimulatory effect of low concentration of GA on cell proliferation, it also eliminated the inhibitory effect of high concentration of GA. Low concentration of GA enhanced the stimulation of AⅡon cell proliferation, while the inhibitory effect of high concentration of GA on cell proliferation was relieved by adding 1×10 -7 mol·L -1 AⅡ. CONCLUSION This study suggests that GA activates transcription factor c-fos and promotes the proliferation of VSMC. GA may exert its effects on cells through AT 1 receptor since it induces similar changes as AⅡ and its effects can be inhibited by AT 1 receptor antagonist.